The present invention relates to a connection verifying device and a connection verifying structure for a pipe and a connector to verify that a pipe correctly snap-fits in and is mechanically connected to a connector which is adapted, for example, in assembly in a gasoline fuel piping of an automobile.
In a fluid piping structure, for example, a gasoline fuel piping structure where a tube is joined to a pipe, a connector is used for joining the tube to the pipe. In such piping system, for example, the pipe is formed with an annular engagement projection on and around an outer peripheral surface of an inserting side to define an inserting end portion. Then, the inserting end portion of the pipe is inserted and fitted in the connector so that the annular engagement projection snap-engages in the connector to provide locking relation between the pipe and the connector. In such a manner, connection between the pipe and the connector is completed. A connector or a quick connector adapted in this manner comprises a tubular connector housing provided with a tube connecting portion on one end of the connector housing along an axis of the connector housing and a retainer holding portion on the other end thereof, and retainer means which is held by the retainer holding portion of the connector housing. The retainer means is formed in an annular or generally annular shape and has, for example, an engagement slit as connection engageable portion or a projecting engagement claw of which one axial end or one axial end portion is formed as connection engageable portion. The inserting end portion of the pipe is inserted in the connector or the connector housing via an opening so that the annular engagement projection of the pipe snap-engages with the engagement slit or the projecting engagement claw, and thereby the pipe is fitted in and mechanically connected to the connector.
Here, the annular engagement projection of the pipe progresses or moves relatively in an axial direction while deforming the retainer means and consequently is engaged with the engagement slit or the projecting engagement claw. Therefore, unless an operator takes care sufficiently to complete connection between the pipe and the connector, the inserting end portion of the pipe might not be fully inserted into the retainer holding portion of the connector housing, or the annular engagement projection might not engage with the engagement slit or the projecting engagement claw of the retainer means. That is, the pipe might be in so-called half-fitting relation with respect to the connector. In case that a piping system is used while the pipe is incompletely connected to the connector, the inserting end of the pipe might move backward or in the other axial direction to a position of sealing member which seals between the connector and the pipe. In this state, sealing property by a sealing member therebetween becomes insufficient, and as a result an inner fluid may leak out.
Then, connection verifying means for a pipe and a connector is demanded in order to verify fit-in relation between the pipe and the connector. As for connection verifying means for a pipe and a connector, such connection verifying device for a pipe and a connector is known which is configured to be fitted to or mounted on a retainer holding portion of a connector housing in which the pipe is inserted to verify that the pipe correctly fits-in or is mechanically connected to the connector (for example, refer to following Document 1 below). If this connection verifying device is adapted, a pipe may be formed with an annular verifying projection on an outer peripheral surface thereof on an end opposite to a leading end of the pipe (or on an end distal to the leading end of the pipe), namely, the other end of the pipe, with respect to an annular engagement projection. Here, when the pipe is in half-fitting relation with respect to a connector, the annular verifying projection is located toward an axial direction away from the tube connecting portion, namely the other axial direction, the connection verifying device cannot be fitted to the connector, a connector housing or a retainer holding portion due to confliction with the annular verifying projection. On the other hand, another connection verifying device is known which cannot be fitted to a connector when a pipe is in half-fitting relation with respect to the connector in spite of without an annular verifying projection (for example, refer to following Document 2 below). In this connecting verifying device, a detector portion of horseshoe-shape in cross-section is slidingly moved in one axial direction on a retainer holding portion so as to be engaged in a stopper portion of the connector housing. Thereby the connection verifying device is mounted on the connector housing while fitting on an outer side of the retainer holding portion. This connection verifying device is configured such that the detector portion cannot be engaged with the stopper portion as a retainer is diametrically expanded when the pipe is in half-fitting relation with respect to the connector. And, when the retainer is not diametrically expanded in spite of half-fitting relation between the pipe and the connector, an annular engagement projection (flange) of the pipe is pushed by a detector piece to move forward, and consequently the retainer is thereby diametrically expanded. However, as the detector portion restrains the retainer from being diametrically expanded and allowing the annular engagement projection of the pipe to pass through, the annular engagement projection stops short of a connection engageable portion of the retainer. Therefore, the detector piece which abuts the annular engagement projection of the pipe disturbs engagement of the detector portion with the stopper portion.
Document 1 JP, A, 2002-213673
Document 2 JP, A, 2001-349487
In the connection verifying device disclosed in the Document 2, an annular verifying projection is not formed on the pipe. However, the detector portion cannot be engaged with the stopper portion when the pipe and the connector are in half-fitting relation, and thereby the pipe is prevented from being used in half-fitting relation with the connection. And, by engaging the detector portion with the stopper portion, it can be verified that the pipe is correctly connected to the connector. Further, the connection verifying device also has a stop function with respect to the pipe, as the detector portion restrain the retainer from diametrically expanding once the connection verifying device is fitted on the connector.
However, in case of adapting this connection verifying device, when an operator finds the pipe and the connector in half-fitting relation, an operator necessarily has to halt mounting of the connection verifying device, push-insert the pipe until the pipe is correctly fitted in and connected to the connector, and then mount the connection verifying device on the connector again. Therefore, when the pipe is in half-fitting relation with respect to the connector, it is troublesome for the operator to connect again the pipe and the connector. In addition, it is fear in this connection verifying device that a projecting engagement claw (stop projection) of the retainer is deformed and the annular engagement projection of the pipe escapes the projecting engagement claw. And, as only one detector piece is provided at one circumferential position, it cannot be sufficiently prevented that the annular engagement projection of the pipe which escapes the projecting engagement claw of the retainer further moves in a direction of escaping the connector. Thus, secure stop function cannot be expected of this connection verifying device.
Accordingly, it is an object of the present invention to provide a connection verifying device for a pipe and a connector having a connection assist function to assist smooth connecting operation of a pipe and a connector and a reliable stop function with respect to the pipe. The connection verifying device of the present invention allows an operator to complete and verifying correct connection between a pipe and a connector in a single continuous uninterrupted connecting operation. It is further object of the present invention to provide a connection verifying structure for a pipe and a connector adapting the connection verifying device.